fs/ext2/super.c

   1 /*
   2  *  linux/fs/ext2/super.c
   3  *
   4  * Copyright (C) 1992, 1993, 1994, 1995
   5  * Remy Card (card@masi.ibp.fr)
   6  * Laboratoire MASI - Institut Blaise Pascal
   7  * Universite Pierre et Marie Curie (Paris VI)
   8  *
   9  *  from
  10  *
  11  *  linux/fs/minix/inode.c
  12  *
  13  *  Copyright (C) 1991, 1992  Linus Torvalds
  14  *
  15  *  Big-endian to little-endian byte-swapping/bitmaps by
  16  *        David S. Miller (davem@caip.rutgers.edu), 1995
  17  */
  18
  19 #include <linux/module.h>
  20 #include <linux/string.h>
  21 #include <linux/fs.h>
  22 #include <linux/slab.h>
  23 #include <linux/init.h>
  24 #include <linux/blkdev.h>
  25 #include <linux/parser.h>
  26 #include <linux/random.h>
  27 #include <linux/buffer_head.h>
  28 #include <linux/smp_lock.h>
  29 #include <linux/vfs.h>
  30 #include <linux/seq_file.h>
  31 #include <linux/mount.h>
  32 #include <asm/uaccess.h>
  33 #include "ext2.h"
  34 #include "xattr.h"
  35 #include "acl.h"
  36 #include "xip.h"
  37
  38 static void ext2_sync_super(struct super_block *sb,
  39                             struct ext2_super_block *es);
  40 static int ext2_remount (struct super_block * sb, int * flags, char * data);
  41 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf);
  42
  43 void ext2_error (struct super_block * sb, const char * function,
  44                  const char * fmt, ...)
  45 {
  46         va_list args;
  47         struct ext2_sb_info *sbi = EXT2_SB(sb);
  48         struct ext2_super_block *es = sbi->s_es;
  49
  50         if (!(sb->s_flags & MS_RDONLY)) {
  51                 sbi->s_mount_state |= EXT2_ERROR_FS;
  52                 es->s_state =
  53                         cpu_to_le16(le16_to_cpu(es->s_state) | EXT2_ERROR_FS);
  54                 ext2_sync_super(sb, es);
  55         }
  56
  57         va_start(args, fmt);
  58         printk(KERN_CRIT "EXT2-fs error (device %s): %s: ",sb->s_id, function);
  59         vprintk(fmt, args);
  60         printk("\n");
  61         va_end(args);
  62
  63         if (test_opt(sb, ERRORS_PANIC))
  64                 panic("EXT2-fs panic from previous error\n");
  65         if (test_opt(sb, ERRORS_RO)) {
  66                 printk("Remounting filesystem read-only\n");
  67                 sb->s_flags |= MS_RDONLY;
  68         }
  69 }
  70
  71 void ext2_warning (struct super_block * sb, const char * function,
  72                    const char * fmt, ...)
  73 {
  74         va_list args;
  75
  76         va_start(args, fmt);
  77         printk(KERN_WARNING "EXT2-fs warning (device %s): %s: ",
  78                sb->s_id, function);
  79         vprintk(fmt, args);
  80         printk("\n");
  81         va_end(args);
  82 }
  83
  84 void ext2_update_dynamic_rev(struct super_block *sb)
  85 {
  86         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
  87
  88         if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
  89                 return;
  90
  91         ext2_warning(sb, __FUNCTION__,
  92                      "updating to rev %d because of new feature flag, "
  93                      "running e2fsck is recommended",
  94                      EXT2_DYNAMIC_REV);
  95
  96         es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
  97         es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
  98         es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
  99         /* leave es->s_feature_*compat flags alone */
 100         /* es->s_uuid will be set by e2fsck if empty */
 101
 102         /*
 103          * The rest of the superblock fields should be zero, and if not it
 104          * means they are likely already in use, so leave them alone.  We
 105          * can leave it up to e2fsck to clean up any inconsistencies there.
 106          */
 107 }
 108
 109 static void ext2_put_super (struct super_block * sb)
 110 {
 111         int db_count;
 112         int i;
 113         struct ext2_sb_info *sbi = EXT2_SB(sb);
 114
 115         ext2_xattr_put_super(sb);
 116         if (!(sb->s_flags & MS_RDONLY)) {
 117                 struct ext2_super_block *es = sbi->s_es;
 118
 119                 es->s_state = cpu_to_le16(sbi->s_mount_state);
 120                 ext2_sync_super(sb, es);
 121         }
 122         db_count = sbi->s_gdb_count;
 123         for (i = 0; i < db_count; i++)
 124                 if (sbi->s_group_desc[i])
 125                         brelse (sbi->s_group_desc[i]);
 126         kfree(sbi->s_group_desc);
 127         kfree(sbi->s_debts);
 128         percpu_counter_destroy(&sbi->s_freeblocks_counter);
 129         percpu_counter_destroy(&sbi->s_freeinodes_counter);
 130         percpu_counter_destroy(&sbi->s_dirs_counter);
 131         brelse (sbi->s_sbh);
 132         sb->s_fs_info = NULL;
 133         kfree(sbi);
 134
 135         return;
 136 }
 137
 138 static kmem_cache_t * ext2_inode_cachep;
 139
 140 static struct inode *ext2_alloc_inode(struct super_block *sb)
 141 {
 142         struct ext2_inode_info *ei;
 143         ei = (struct ext2_inode_info *)kmem_cache_alloc(ext2_inode_cachep, SLAB_KERNEL);
 144         if (!ei)
 145                 return NULL;
 146 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 147         ei->i_acl = EXT2_ACL_NOT_CACHED;
 148         ei->i_default_acl = EXT2_ACL_NOT_CACHED;
 149 #endif
 150         ei->vfs_inode.i_version = 1;
 151         return &ei->vfs_inode;
 152 }
 153
 154 static void ext2_destroy_inode(struct inode *inode)
 155 {
 156         kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
 157 }
 158
 159 static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
 160 {
 161         struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
 162
 163         if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
 164             SLAB_CTOR_CONSTRUCTOR) {
 165                 rwlock_init(&ei->i_meta_lock);
 166 #ifdef CONFIG_EXT2_FS_XATTR
 167                 init_rwsem(&ei->xattr_sem);
 168 #endif
 169                 inode_init_once(&ei->vfs_inode);
 170         }
 171 }
 172
 173 static int init_inodecache(void)
 174 {
 175         ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
 176                                              sizeof(struct ext2_inode_info),
 177                                              0, (SLAB_RECLAIM_ACCOUNT|
 178                                                 SLAB_MEM_SPREAD),
 179                                              init_once, NULL);
 180         if (ext2_inode_cachep == NULL)
 181                 return -ENOMEM;
 182         return 0;
 183 }
 184
 185 static void destroy_inodecache(void)
 186 {
 187         if (kmem_cache_destroy(ext2_inode_cachep))
 188                 printk(KERN_INFO "ext2_inode_cache: not all structures were freed\n");
 189 }
 190
 191 static void ext2_clear_inode(struct inode *inode)
 192 {
 193 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 194         struct ext2_inode_info *ei = EXT2_I(inode);
 195
 196         if (ei->i_acl && ei->i_acl != EXT2_ACL_NOT_CACHED) {
 197                 posix_acl_release(ei->i_acl);
 198                 ei->i_acl = EXT2_ACL_NOT_CACHED;
 199         }
 200         if (ei->i_default_acl && ei->i_default_acl != EXT2_ACL_NOT_CACHED) {
 201                 posix_acl_release(ei->i_default_acl);
 202                 ei->i_default_acl = EXT2_ACL_NOT_CACHED;
 203         }
 204 #endif
 205 }
 206
 207 static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs)
 208 {
 209         struct ext2_sb_info *sbi = EXT2_SB(vfs->mnt_sb);
 210
 211         if (sbi->s_mount_opt & EXT2_MOUNT_GRPID)
 212                 seq_puts(seq, ",grpid");
 213
 214 #if defined(CONFIG_QUOTA)
 215         if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
 216                 seq_puts(seq, ",usrquota");
 217
 218         if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
 219                 seq_puts(seq, ",grpquota");
 220 #endif
 221
 222 #if defined(CONFIG_EXT2_FS_XIP)
 223         if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
 224                 seq_puts(seq, ",xip");
 225 #endif
 226
 227         return 0;
 228 }
 229
 230 #ifdef CONFIG_QUOTA
 231 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
 232 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
 233 #endif
 234
 235 static struct super_operations ext2_sops = {
 236         .alloc_inode    = ext2_alloc_inode,
 237         .destroy_inode  = ext2_destroy_inode,
 238         .read_inode     = ext2_read_inode,
 239         .write_inode    = ext2_write_inode,
 240         .put_inode      = ext2_put_inode,
 241         .delete_inode   = ext2_delete_inode,
 242         .put_super      = ext2_put_super,
 243         .write_super    = ext2_write_super,
 244         .statfs         = ext2_statfs,
 245         .remount_fs     = ext2_remount,
 246         .clear_inode    = ext2_clear_inode,
 247         .show_options   = ext2_show_options,
 248 #ifdef CONFIG_QUOTA
 249         .quota_read     = ext2_quota_read,
 250         .quota_write    = ext2_quota_write,
 251 #endif
 252 };
 253
 254 static struct dentry *ext2_get_dentry(struct super_block *sb, void *vobjp)
 255 {
 256         __u32 *objp = vobjp;
 257         unsigned long ino = objp[0];
 258         __u32 generation = objp[1];
 259         struct inode *inode;
 260         struct dentry *result;
 261
 262         if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
 263                 return ERR_PTR(-ESTALE);
 264         if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
 265                 return ERR_PTR(-ESTALE);
 266
 267         /* iget isn't really right if the inode is currently unallocated!!
 268          * ext2_read_inode currently does appropriate checks, but
 269          * it might be "neater" to call ext2_get_inode first and check
 270          * if the inode is valid.....
 271          */
 272         inode = iget(sb, ino);
 273         if (inode == NULL)
 274                 return ERR_PTR(-ENOMEM);
 275         if (is_bad_inode(inode) ||
 276             (generation && inode->i_generation != generation)) {
 277                 /* we didn't find the right inode.. */
 278                 iput(inode);
 279                 return ERR_PTR(-ESTALE);
 280         }
 281         /* now to find a dentry.
 282          * If possible, get a well-connected one
 283          */
 284         result = d_alloc_anon(inode);
 285         if (!result) {
 286                 iput(inode);
 287                 return ERR_PTR(-ENOMEM);
 288         }
 289         return result;
 290 }
 291
 292 /* Yes, most of these are left as NULL!!
 293  * A NULL value implies the default, which works with ext2-like file
 294  * systems, but can be improved upon.
 295  * Currently only get_parent is required.
 296  */
 297 static struct export_operations ext2_export_ops = {
 298         .get_parent = ext2_get_parent,
 299         .get_dentry = ext2_get_dentry,
 300 };
 301
 302 static unsigned long get_sb_block(void **data)
 303 {
 304         unsigned long   sb_block;
 305         char            *options = (char *) *data;
 306
 307         if (!options || strncmp(options, "sb=", 3) != 0)
 308                 return 1;       /* Default location */
 309         options += 3;
 310         sb_block = simple_strtoul(options, &options, 0);
 311         if (*options && *options != ',') {
 312                 printk("EXT2-fs: Invalid sb specification: %s\n",
 313                        (char *) *data);
 314                 return 1;
 315         }
 316         if (*options == ',')
 317                 options++;
 318         *data = (void *) options;
 319         return sb_block;
 320 }
 321
 322 enum {
 323         Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
 324         Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
 325         Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
 326         Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
 327         Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
 328         Opt_usrquota, Opt_grpquota
 329 };
 330
 331 static match_table_t tokens = {
 332         {Opt_bsd_df, "bsddf"},
 333         {Opt_minix_df, "minixdf"},
 334         {Opt_grpid, "grpid"},
 335         {Opt_grpid, "bsdgroups"},
 336         {Opt_nogrpid, "nogrpid"},
 337         {Opt_nogrpid, "sysvgroups"},
 338         {Opt_resgid, "resgid=%u"},
 339         {Opt_resuid, "resuid=%u"},
 340         {Opt_sb, "sb=%u"},
 341         {Opt_err_cont, "errors=continue"},
 342         {Opt_err_panic, "errors=panic"},
 343         {Opt_err_ro, "errors=remount-ro"},
 344         {Opt_nouid32, "nouid32"},
 345         {Opt_nocheck, "check=none"},
 346         {Opt_nocheck, "nocheck"},
 347         {Opt_debug, "debug"},
 348         {Opt_oldalloc, "oldalloc"},
 349         {Opt_orlov, "orlov"},
 350         {Opt_nobh, "nobh"},
 351         {Opt_user_xattr, "user_xattr"},
 352         {Opt_nouser_xattr, "nouser_xattr"},
 353         {Opt_acl, "acl"},
 354         {Opt_noacl, "noacl"},
 355         {Opt_xip, "xip"},
 356         {Opt_grpquota, "grpquota"},
 357         {Opt_ignore, "noquota"},
 358         {Opt_quota, "quota"},
 359         {Opt_usrquota, "usrquota"},
 360         {Opt_err, NULL}
 361 };
 362
 363 static int parse_options (char * options,
 364                           struct ext2_sb_info *sbi)
 365 {
 366         char * p;
 367         substring_t args[MAX_OPT_ARGS];
 368         unsigned long kind = EXT2_MOUNT_ERRORS_CONT;
 369         int option;
 370
 371         if (!options)
 372                 return 1;
 373
 374         while ((p = strsep (&options, ",")) != NULL) {
 375                 int token;
 376                 if (!*p)
 377                         continue;
 378
 379                 token = match_token(p, tokens, args);
 380                 switch (token) {
 381                 case Opt_bsd_df:
 382                         clear_opt (sbi->s_mount_opt, MINIX_DF);
 383                         break;
 384                 case Opt_minix_df:
 385                         set_opt (sbi->s_mount_opt, MINIX_DF);
 386                         break;
 387                 case Opt_grpid:
 388                         set_opt (sbi->s_mount_opt, GRPID);
 389                         break;
 390                 case Opt_nogrpid:
 391                         clear_opt (sbi->s_mount_opt, GRPID);
 392                         break;
 393                 case Opt_resuid:
 394                         if (match_int(&args[0], &option))
 395                                 return 0;
 396                         sbi->s_resuid = option;
 397                         break;
 398                 case Opt_resgid:
 399                         if (match_int(&args[0], &option))
 400                                 return 0;
 401                         sbi->s_resgid = option;
 402                         break;
 403                 case Opt_sb:
 404                         /* handled by get_sb_block() instead of here */
 405                         /* *sb_block = match_int(&args[0]); */
 406                         break;
 407                 case Opt_err_panic:
 408                         kind = EXT2_MOUNT_ERRORS_PANIC;
 409                         break;
 410                 case Opt_err_ro:
 411                         kind = EXT2_MOUNT_ERRORS_RO;
 412                         break;
 413                 case Opt_err_cont:
 414                         kind = EXT2_MOUNT_ERRORS_CONT;
 415                         break;
 416                 case Opt_nouid32:
 417                         set_opt (sbi->s_mount_opt, NO_UID32);
 418                         break;
 419                 case Opt_nocheck:
 420                         clear_opt (sbi->s_mount_opt, CHECK);
 421                         break;
 422                 case Opt_debug:
 423                         set_opt (sbi->s_mount_opt, DEBUG);
 424                         break;
 425                 case Opt_oldalloc:
 426                         set_opt (sbi->s_mount_opt, OLDALLOC);
 427                         break;
 428                 case Opt_orlov:
 429                         clear_opt (sbi->s_mount_opt, OLDALLOC);
 430                         break;
 431                 case Opt_nobh:
 432                         set_opt (sbi->s_mount_opt, NOBH);
 433                         break;
 434 #ifdef CONFIG_EXT2_FS_XATTR
 435                 case Opt_user_xattr:
 436                         set_opt (sbi->s_mount_opt, XATTR_USER);
 437                         break;
 438                 case Opt_nouser_xattr:
 439                         clear_opt (sbi->s_mount_opt, XATTR_USER);
 440                         break;
 441 #else
 442                 case Opt_user_xattr:
 443                 case Opt_nouser_xattr:
 444                         printk("EXT2 (no)user_xattr options not supported\n");
 445                         break;
 446 #endif
 447 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 448                 case Opt_acl:
 449                         set_opt(sbi->s_mount_opt, POSIX_ACL);
 450                         break;
 451                 case Opt_noacl:
 452                         clear_opt(sbi->s_mount_opt, POSIX_ACL);
 453                         break;
 454 #else
 455                 case Opt_acl:
 456                 case Opt_noacl:
 457                         printk("EXT2 (no)acl options not supported\n");
 458                         break;
 459 #endif
 460                 case Opt_xip:
 461 #ifdef CONFIG_EXT2_FS_XIP
 462                         set_opt (sbi->s_mount_opt, XIP);
 463 #else
 464                         printk("EXT2 xip option not supported\n");
 465 #endif
 466                         break;
 467
 468 #if defined(CONFIG_QUOTA)
 469                 case Opt_quota:
 470                 case Opt_usrquota:
 471                         set_opt(sbi->s_mount_opt, USRQUOTA);
 472                         break;
 473
 474                 case Opt_grpquota:
 475                         set_opt(sbi->s_mount_opt, GRPQUOTA);
 476                         break;
 477 #else
 478                 case Opt_quota:
 479                 case Opt_usrquota:
 480                 case Opt_grpquota:
 481                         printk(KERN_ERR
 482                                 "EXT2-fs: quota operations not supported.\n");
 483
 484                         break;
 485 #endif
 486
 487                 case Opt_ignore:
 488                         break;
 489                 default:
 490                         return 0;
 491                 }
 492         }
 493         sbi->s_mount_opt |= kind;
 494         return 1;
 495 }
 496
 497 static int ext2_setup_super (struct super_block * sb,
 498                               struct ext2_super_block * es,
 499                               int read_only)
 500 {
 501         int res = 0;
 502         struct ext2_sb_info *sbi = EXT2_SB(sb);
 503
 504         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
 505                 printk ("EXT2-fs warning: revision level too high, "
 506                         "forcing read-only mode\n");
 507                 res = MS_RDONLY;
 508         }
 509         if (read_only)
 510                 return res;
 511         if (!(sbi->s_mount_state & EXT2_VALID_FS))
 512                 printk ("EXT2-fs warning: mounting unchecked fs, "
 513                         "running e2fsck is recommended\n");
 514         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
 515                 printk ("EXT2-fs warning: mounting fs with errors, "
 516                         "running e2fsck is recommended\n");
 517         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
 518                  le16_to_cpu(es->s_mnt_count) >=
 519                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
 520                 printk ("EXT2-fs warning: maximal mount count reached, "
 521                         "running e2fsck is recommended\n");
 522         else if (le32_to_cpu(es->s_checkinterval) &&
 523                 (le32_to_cpu(es->s_lastcheck) + le32_to_cpu(es->s_checkinterval) <= get_seconds()))
 524                 printk ("EXT2-fs warning: checktime reached, "
 525                         "running e2fsck is recommended\n");
 526         if (!le16_to_cpu(es->s_max_mnt_count))
 527                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
 528         es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
 529         ext2_write_super(sb);
 530         if (test_opt (sb, DEBUG))
 531                 printk ("[EXT II FS %s, %s, bs=%lu, fs=%lu, gc=%lu, "
 532                         "bpg=%lu, ipg=%lu, mo=%04lx]\n",
 533                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
 534                         sbi->s_frag_size,
 535                         sbi->s_groups_count,
 536                         EXT2_BLOCKS_PER_GROUP(sb),
 537                         EXT2_INODES_PER_GROUP(sb),
 538                         sbi->s_mount_opt);
 539         return res;
 540 }
 541
 542 static int ext2_check_descriptors (struct super_block * sb)
 543 {
 544         int i;
 545         int desc_block = 0;
 546         struct ext2_sb_info *sbi = EXT2_SB(sb);
 547         unsigned long block = le32_to_cpu(sbi->s_es->s_first_data_block);
 548         struct ext2_group_desc * gdp = NULL;
 549
 550         ext2_debug ("Checking group descriptors");
 551
 552         for (i = 0; i < sbi->s_groups_count; i++)
 553         {
 554                 if ((i % EXT2_DESC_PER_BLOCK(sb)) == 0)
 555                         gdp = (struct ext2_group_desc *) sbi->s_group_desc[desc_block++]->b_data;
 556                 if (le32_to_cpu(gdp->bg_block_bitmap) < block ||
 557                     le32_to_cpu(gdp->bg_block_bitmap) >= block + EXT2_BLOCKS_PER_GROUP(sb))
 558                 {
 559                         ext2_error (sb, "ext2_check_descriptors",
 560                                     "Block bitmap for group %d"
 561                                     " not in group (block %lu)!",
 562                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
 563                         return 0;
 564                 }
 565                 if (le32_to_cpu(gdp->bg_inode_bitmap) < block ||
 566                     le32_to_cpu(gdp->bg_inode_bitmap) >= block + EXT2_BLOCKS_PER_GROUP(sb))
 567                 {
 568                         ext2_error (sb, "ext2_check_descriptors",
 569                                     "Inode bitmap for group %d"
 570                                     " not in group (block %lu)!",
 571                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
 572                         return 0;
 573                 }
 574                 if (le32_to_cpu(gdp->bg_inode_table) < block ||
 575                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group >=
 576                     block + EXT2_BLOCKS_PER_GROUP(sb))
 577                 {
 578                         ext2_error (sb, "ext2_check_descriptors",
 579                                     "Inode table for group %d"
 580                                     " not in group (block %lu)!",
 581                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
 582                         return 0;
 583                 }
 584                 block += EXT2_BLOCKS_PER_GROUP(sb);
 585                 gdp++;
 586         }
 587         return 1;
 588 }
 589
 590 #define log2(n) ffz(~(n))
 591
 592 /*
 593  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
 594  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
 595  * We need to be 1 filesystem block less than the 2^32 sector limit.
 596  */
 597 static loff_t ext2_max_size(int bits)
 598 {
 599         loff_t res = EXT2_NDIR_BLOCKS;
 600         /* This constant is calculated to be the largest file size for a
 601          * dense, 4k-blocksize file such that the total number of
 602          * sectors in the file, including data and all indirect blocks,
 603          * does not exceed 2^32. */
 604         const loff_t upper_limit = 0x1ff7fffd000LL;
 605
 606         res += 1LL << (bits-2);
 607         res += 1LL << (2*(bits-2));
 608         res += 1LL << (3*(bits-2));
 609         res <<= bits;
 610         if (res > upper_limit)
 611                 res = upper_limit;
 612         return res;
 613 }
 614
 615 static unsigned long descriptor_loc(struct super_block *sb,
 616                                     unsigned long logic_sb_block,
 617                                     int nr)
 618 {
 619         struct ext2_sb_info *sbi = EXT2_SB(sb);
 620         unsigned long bg, first_data_block, first_meta_bg;
 621         int has_super = 0;
 622
 623         first_data_block = le32_to_cpu(sbi->s_es->s_first_data_block);
 624         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
 625
 626         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
 627             nr < first_meta_bg)
 628                 return (logic_sb_block + nr + 1);
 629         bg = sbi->s_desc_per_block * nr;
 630         if (ext2_bg_has_super(sb, bg))
 631                 has_super = 1;
 632         return (first_data_block + has_super + (bg * sbi->s_blocks_per_group));
 633 }
 634
 635 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 636 {
 637         struct buffer_head * bh;
 638         struct ext2_sb_info * sbi;
 639         struct ext2_super_block * es;
 640         struct inode *root;
 641         unsigned long block;
 642         unsigned long sb_block = get_sb_block(&data);
 643         unsigned long logic_sb_block;
 644         unsigned long offset = 0;
 645         unsigned long def_mount_opts;
 646         int blocksize = BLOCK_SIZE;
 647         int db_count;
 648         int i, j;
 649         __le32 features;
 650
 651         sbi = kmalloc(sizeof(*sbi), GFP_KERNEL);
 652         if (!sbi)
 653                 return -ENOMEM;
 654         sb->s_fs_info = sbi;
 655         memset(sbi, 0, sizeof(*sbi));
 656
 657         /*
 658          * See what the current blocksize for the device is, and
 659          * use that as the blocksize.  Otherwise (or if the blocksize
 660          * is smaller than the default) use the default.
 661          * This is important for devices that have a hardware
 662          * sectorsize that is larger than the default.
 663          */
 664         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
 665         if (!blocksize) {
 666                 printk ("EXT2-fs: unable to set blocksize\n");
 667                 goto failed_sbi;
 668         }
 669
 670         /*
 671          * If the superblock doesn't start on a hardware sector boundary,
 672          * calculate the offset.
 673          */
 674         if (blocksize != BLOCK_SIZE) {
 675                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 676                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 677         } else {
 678                 logic_sb_block = sb_block;
 679         }
 680
 681         if (!(bh = sb_bread(sb, logic_sb_block))) {
 682                 printk ("EXT2-fs: unable to read superblock\n");
 683                 goto failed_sbi;
 684         }
 685         /*
 686          * Note: s_es must be initialized as soon as possible because
 687          *       some ext2 macro-instructions depend on its value
 688          */
 689         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 690         sbi->s_es = es;
 691         sb->s_magic = le16_to_cpu(es->s_magic);
 692
 693         if (sb->s_magic != EXT2_SUPER_MAGIC)
 694                 goto cantfind_ext2;
 695
 696         /* Set defaults before we parse the mount options */
 697         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 698         if (def_mount_opts & EXT2_DEFM_DEBUG)
 699                 set_opt(sbi->s_mount_opt, DEBUG);
 700         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
 701                 set_opt(sbi->s_mount_opt, GRPID);
 702         if (def_mount_opts & EXT2_DEFM_UID16)
 703                 set_opt(sbi->s_mount_opt, NO_UID32);
 704         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
 705                 set_opt(sbi->s_mount_opt, XATTR_USER);
 706         if (def_mount_opts & EXT2_DEFM_ACL)
 707                 set_opt(sbi->s_mount_opt, POSIX_ACL);
 708
 709         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
 710                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
 711         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_RO)
 712                 set_opt(sbi->s_mount_opt, ERRORS_RO);
 713
 714         sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
 715         sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
 716
 717         if (!parse_options ((char *) data, sbi))
 718                 goto failed_mount;
 719
 720         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 721                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
 722                  MS_POSIXACL : 0);
 723
 724         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
 725                                     EXT2_MOUNT_XIP if not */
 726
 727         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
 728             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
 729              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
 730              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
 731                 printk("EXT2-fs warning: feature flags set on rev 0 fs, "
 732                        "running e2fsck is recommended\n");
 733         /*
 734          * Check feature flags regardless of the revision level, since we
 735          * previously didn't change the revision level when setting the flags,
 736          * so there is a chance incompat flags are set on a rev 0 filesystem.
 737          */
 738         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
 739         if (features) {
 740                 printk("EXT2-fs: %s: couldn't mount because of "
 741                        "unsupported optional features (%x).\n",
 742                        sb->s_id, le32_to_cpu(features));
 743                 goto failed_mount;
 744         }
 745         if (!(sb->s_flags & MS_RDONLY) &&
 746             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
 747                 printk("EXT2-fs: %s: couldn't mount RDWR because of "
 748                        "unsupported optional features (%x).\n",
 749                        sb->s_id, le32_to_cpu(features));
 750                 goto failed_mount;
 751         }
 752
 753         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
 754
 755         if ((ext2_use_xip(sb)) && ((blocksize != PAGE_SIZE) ||
 756                                   (sb->s_blocksize != blocksize))) {
 757                 if (!silent)
 758                         printk("XIP: Unsupported blocksize\n");
 759                 goto failed_mount;
 760         }
 761
 762         /* If the blocksize doesn't match, re-read the thing.. */
 763         if (sb->s_blocksize != blocksize) {
 764                 brelse(bh);
 765
 766                 if (!sb_set_blocksize(sb, blocksize)) {
 767                         printk(KERN_ERR "EXT2-fs: blocksize too small for device.\n");
 768                         goto failed_sbi;
 769                 }
 770
 771                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 772                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 773                 bh = sb_bread(sb, logic_sb_block);
 774                 if(!bh) {
 775                         printk("EXT2-fs: Couldn't read superblock on "
 776                                "2nd try.\n");
 777                         goto failed_sbi;
 778                 }
 779                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 780                 sbi->s_es = es;
 781                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
 782                         printk ("EXT2-fs: Magic mismatch, very weird !\n");
 783                         goto failed_mount;
 784                 }
 785         }
 786
 787         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
 788
 789         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
 790                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
 791                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
 792         } else {
 793                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
 794                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
 795                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
 796                     (sbi->s_inode_size & (sbi->s_inode_size - 1)) ||
 797                     (sbi->s_inode_size > blocksize)) {
 798                         printk ("EXT2-fs: unsupported inode size: %d\n",
 799                                 sbi->s_inode_size);
 800                         goto failed_mount;
 801                 }
 802         }
 803
 804         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
 805                                    le32_to_cpu(es->s_log_frag_size);
 806         if (sbi->s_frag_size == 0)
 807                 goto cantfind_ext2;
 808         sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
 809
 810         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
 811         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
 812         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
 813
 814         if (EXT2_INODE_SIZE(sb) == 0)
 815                 goto cantfind_ext2;
 816         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
 817         if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
 818                 goto cantfind_ext2;
 819         sbi->s_itb_per_group = sbi->s_inodes_per_group /
 820                                         sbi->s_inodes_per_block;
 821         sbi->s_desc_per_block = sb->s_blocksize /
 822                                         sizeof (struct ext2_group_desc);
 823         sbi->s_sbh = bh;
 824         sbi->s_mount_state = le16_to_cpu(es->s_state);
 825         sbi->s_addr_per_block_bits =
 826                 log2 (EXT2_ADDR_PER_BLOCK(sb));
 827         sbi->s_desc_per_block_bits =
 828                 log2 (EXT2_DESC_PER_BLOCK(sb));
 829
 830         if (sb->s_magic != EXT2_SUPER_MAGIC)
 831                 goto cantfind_ext2;
 832
 833         if (sb->s_blocksize != bh->b_size) {
 834                 if (!silent)
 835                         printk ("VFS: Unsupported blocksize on dev "
 836                                 "%s.\n", sb->s_id);
 837                 goto failed_mount;
 838         }
 839
 840         if (sb->s_blocksize != sbi->s_frag_size) {
 841                 printk ("EXT2-fs: fragsize %lu != blocksize %lu (not supported yet)\n",
 842                         sbi->s_frag_size, sb->s_blocksize);
 843                 goto failed_mount;
 844         }
 845
 846         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
 847                 printk ("EXT2-fs: #blocks per group too big: %lu\n",
 848                         sbi->s_blocks_per_group);
 849                 goto failed_mount;
 850         }
 851         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
 852                 printk ("EXT2-fs: #fragments per group too big: %lu\n",
 853                         sbi->s_frags_per_group);
 854                 goto failed_mount;
 855         }
 856         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
 857                 printk ("EXT2-fs: #inodes per group too big: %lu\n",
 858                         sbi->s_inodes_per_group);
 859                 goto failed_mount;
 860         }
 861
 862         if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
 863                 goto cantfind_ext2;
 864         sbi->s_groups_count = (le32_to_cpu(es->s_blocks_count) -
 865                                         le32_to_cpu(es->s_first_data_block) +
 866                                        EXT2_BLOCKS_PER_GROUP(sb) - 1) /
 867                                        EXT2_BLOCKS_PER_GROUP(sb);
 868         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
 869                    EXT2_DESC_PER_BLOCK(sb);
 870         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
 871         if (sbi->s_group_desc == NULL) {
 872                 printk ("EXT2-fs: not enough memory\n");
 873                 goto failed_mount;
 874         }
 875         bgl_lock_init(&sbi->s_blockgroup_lock);
 876         sbi->s_debts = kmalloc(sbi->s_groups_count * sizeof(*sbi->s_debts),
 877                                GFP_KERNEL);
 878         if (!sbi->s_debts) {
 879                 printk ("EXT2-fs: not enough memory\n");
 880                 goto failed_mount_group_desc;
 881         }
 882         memset(sbi->s_debts, 0, sbi->s_groups_count * sizeof(*sbi->s_debts));
 883         for (i = 0; i < db_count; i++) {
 884                 block = descriptor_loc(sb, logic_sb_block, i);
 885                 sbi->s_group_desc[i] = sb_bread(sb, block);
 886                 if (!sbi->s_group_desc[i]) {
 887                         for (j = 0; j < i; j++)
 888                                 brelse (sbi->s_group_desc[j]);
 889                         printk ("EXT2-fs: unable to read group descriptors\n");
 890                         goto failed_mount_group_desc;
 891                 }
 892         }
 893         if (!ext2_check_descriptors (sb)) {
 894                 printk ("EXT2-fs: group descriptors corrupted!\n");
 895                 goto failed_mount2;
 896         }
 897         sbi->s_gdb_count = db_count;
 898         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
 899         spin_lock_init(&sbi->s_next_gen_lock);
 900
 901         percpu_counter_init(&sbi->s_freeblocks_counter,
 902                                 ext2_count_free_blocks(sb));
 903         percpu_counter_init(&sbi->s_freeinodes_counter,
 904                                 ext2_count_free_inodes(sb));
 905         percpu_counter_init(&sbi->s_dirs_counter,
 906                                 ext2_count_dirs(sb));
 907         /*
 908          * set up enough so that it can read an inode
 909          */
 910         sb->s_op = &ext2_sops;
 911         sb->s_export_op = &ext2_export_ops;
 912         sb->s_xattr = ext2_xattr_handlers;
 913         root = iget(sb, EXT2_ROOT_INO);
 914         sb->s_root = d_alloc_root(root);
 915         if (!sb->s_root) {
 916                 iput(root);
 917                 printk(KERN_ERR "EXT2-fs: get root inode failed\n");
 918                 goto failed_mount3;
 919         }
 920         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
 921                 dput(sb->s_root);
 922                 sb->s_root = NULL;
 923                 printk(KERN_ERR "EXT2-fs: corrupt root inode, run e2fsck\n");
 924                 goto failed_mount3;
 925         }
 926         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
 927                 ext2_warning(sb, __FUNCTION__,
 928                         "mounting ext3 filesystem as ext2");
 929         ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
 930         return 0;
 931
 932 cantfind_ext2:
 933         if (!silent)
 934                 printk("VFS: Can't find an ext2 filesystem on dev %s.\n",
 935                        sb->s_id);
 936         goto failed_mount;
 937 failed_mount3:
 938         percpu_counter_destroy(&sbi->s_freeblocks_counter);
 939         percpu_counter_destroy(&sbi->s_freeinodes_counter);
 940         percpu_counter_destroy(&sbi->s_dirs_counter);
 941 failed_mount2:
 942         for (i = 0; i < db_count; i++)
 943                 brelse(sbi->s_group_desc[i]);
 944 failed_mount_group_desc:
 945         kfree(sbi->s_group_desc);
 946         kfree(sbi->s_debts);
 947 failed_mount:
 948         brelse(bh);
 949 failed_sbi:
 950         sb->s_fs_info = NULL;
 951         kfree(sbi);
 952         return -EINVAL;
 953 }
 954
 955 static void ext2_commit_super (struct super_block * sb,
 956                                struct ext2_super_block * es)
 957 {
 958         es->s_wtime = cpu_to_le32(get_seconds());
 959         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
 960         sb->s_dirt = 0;
 961 }
 962
 963 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
 964 {
 965         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
 966         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
 967         es->s_wtime = cpu_to_le32(get_seconds());
 968         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
 969         sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
 970         sb->s_dirt = 0;
 971 }
 972
 973 /*
 974  * In the second extended file system, it is not necessary to
 975  * write the super block since we use a mapping of the
 976  * disk super block in a buffer.
 977  *
 978  * However, this function is still used to set the fs valid
 979  * flags to 0.  We need to set this flag to 0 since the fs
 980  * may have been checked while mounted and e2fsck may have
 981  * set s_state to EXT2_VALID_FS after some corrections.
 982  */
 983
 984 void ext2_write_super (struct super_block * sb)
 985 {
 986         struct ext2_super_block * es;
 987         lock_kernel();
 988         if (!(sb->s_flags & MS_RDONLY)) {
 989                 es = EXT2_SB(sb)->s_es;
 990
 991                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS) {
 992                         ext2_debug ("setting valid to 0\n");
 993                         es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) &
 994                                                   ~EXT2_VALID_FS);
 995                         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
 996                         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
 997                         es->s_mtime = cpu_to_le32(get_seconds());
 998                         ext2_sync_super(sb, es);
 999                 } else
1000                         ext2_commit_super (sb, es);
1001         }
1002         sb->s_dirt = 0;
1003         unlock_kernel();
1004 }
1005
1006 static int ext2_remount (struct super_block * sb, int * flags, char * data)
1007 {
1008         struct ext2_sb_info * sbi = EXT2_SB(sb);
1009         struct ext2_super_block * es;
1010         unsigned long old_mount_opt = sbi->s_mount_opt;
1011         struct ext2_mount_options old_opts;
1012         unsigned long old_sb_flags;
1013         int err;
1014
1015         /* Store the old options */
1016         old_sb_flags = sb->s_flags;
1017         old_opts.s_mount_opt = sbi->s_mount_opt;
1018         old_opts.s_resuid = sbi->s_resuid;
1019         old_opts.s_resgid = sbi->s_resgid;
1020
1021         /*
1022          * Allow the "check" option to be passed as a remount option.
1023          */
1024         if (!parse_options (data, sbi)) {
1025                 err = -EINVAL;
1026                 goto restore_opts;
1027         }
1028
1029         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1030                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1031
1032         es = sbi->s_es;
1033         if (((sbi->s_mount_opt & EXT2_MOUNT_XIP) !=
1034             (old_mount_opt & EXT2_MOUNT_XIP)) &&
1035             invalidate_inodes(sb))
1036                 ext2_warning(sb, __FUNCTION__, "busy inodes while remounting "\
1037                              "xip remain in cache (no functional problem)");
1038         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1039                 return 0;
1040         if (*flags & MS_RDONLY) {
1041                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1042                     !(sbi->s_mount_state & EXT2_VALID_FS))
1043                         return 0;
1044                 /*
1045                  * OK, we are remounting a valid rw partition rdonly, so set
1046                  * the rdonly flag and then mark the partition as valid again.
1047                  */
1048                 es->s_state = cpu_to_le16(sbi->s_mount_state);
1049                 es->s_mtime = cpu_to_le32(get_seconds());
1050         } else {
1051                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1052                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
1053                 if (ret) {
1054                         printk("EXT2-fs: %s: couldn't remount RDWR because of "
1055                                "unsupported optional features (%x).\n",
1056                                sb->s_id, le32_to_cpu(ret));
1057                         err = -EROFS;
1058                         goto restore_opts;
1059                 }
1060                 /*
1061                  * Mounting a RDONLY partition read-write, so reread and
1062                  * store the current valid flag.  (It may have been changed
1063                  * by e2fsck since we originally mounted the partition.)
1064                  */
1065                 sbi->s_mount_state = le16_to_cpu(es->s_state);
1066                 if (!ext2_setup_super (sb, es, 0))
1067                         sb->s_flags &= ~MS_RDONLY;
1068         }
1069         ext2_sync_super(sb, es);
1070         return 0;
1071 restore_opts:
1072         sbi->s_mount_opt = old_opts.s_mount_opt;
1073         sbi->s_resuid = old_opts.s_resuid;
1074         sbi->s_resgid = old_opts.s_resgid;
1075         sb->s_flags = old_sb_flags;
1076         return err;
1077 }
1078
1079 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1080 {
1081         struct super_block *sb = dentry->d_sb;
1082         struct ext2_sb_info *sbi = EXT2_SB(sb);
1083         unsigned long overhead;
1084         int i;
1085
1086         if (test_opt (sb, MINIX_DF))
1087                 overhead = 0;
1088         else {
1089                 /*
1090                  * Compute the overhead (FS structures)
1091                  */
1092
1093                 /*
1094                  * All of the blocks before first_data_block are
1095                  * overhead
1096                  */
1097                 overhead = le32_to_cpu(sbi->s_es->s_first_data_block);
1098
1099                 /*
1100                  * Add the overhead attributed to the superblock and
1101                  * block group descriptors.  If the sparse superblocks
1102                  * feature is turned on, then not all groups have this.
1103                  */
1104                 for (i = 0; i < sbi->s_groups_count; i++)
1105                         overhead += ext2_bg_has_super(sb, i) +
1106                                 ext2_bg_num_gdb(sb, i);
1107
1108                 /*
1109                  * Every block group has an inode bitmap, a block
1110                  * bitmap, and an inode table.
1111                  */
1112                 overhead += (sbi->s_groups_count *
1113                              (2 + sbi->s_itb_per_group));
1114         }
1115
1116         buf->f_type = EXT2_SUPER_MAGIC;
1117         buf->f_bsize = sb->s_blocksize;
1118         buf->f_blocks = le32_to_cpu(sbi->s_es->s_blocks_count) - overhead;
1119         buf->f_bfree = ext2_count_free_blocks(sb);
1120         buf->f_bavail = buf->f_bfree - le32_to_cpu(sbi->s_es->s_r_blocks_count);
1121         if (buf->f_bfree < le32_to_cpu(sbi->s_es->s_r_blocks_count))
1122                 buf->f_bavail = 0;
1123         buf->f_files = le32_to_cpu(sbi->s_es->s_inodes_count);
1124         buf->f_ffree = ext2_count_free_inodes (sb);
1125         buf->f_namelen = EXT2_NAME_LEN;
1126         return 0;
1127 }
1128
1129 static int ext2_get_sb(struct file_system_type *fs_type,
1130         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
1131 {
1132         return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super, mnt);
1133 }
1134
1135 #ifdef CONFIG_QUOTA
1136
1137 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1138  * acquiring the locks... As quota files are never truncated and quota code
1139  * itself serializes the operations (and noone else should touch the files)
1140  * we don't have to be afraid of races */
1141 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1142                                size_t len, loff_t off)
1143 {
1144         struct inode *inode = sb_dqopt(sb)->files[type];
1145         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1146         int err = 0;
1147         int offset = off & (sb->s_blocksize - 1);
1148         int tocopy;
1149         size_t toread;
1150         struct buffer_head tmp_bh;
1151         struct buffer_head *bh;
1152         loff_t i_size = i_size_read(inode);
1153
1154         if (off > i_size)
1155                 return 0;
1156         if (off+len > i_size)
1157                 len = i_size-off;
1158         toread = len;
1159         while (toread > 0) {
1160                 tocopy = sb->s_blocksize - offset < toread ?
1161                                 sb->s_blocksize - offset : toread;
1162
1163                 tmp_bh.b_state = 0;
1164                 err = ext2_get_block(inode, blk, &tmp_bh, 0);
1165                 if (err)
1166                         return err;
1167                 if (!buffer_mapped(&tmp_bh))    /* A hole? */
1168                         memset(data, 0, tocopy);
1169                 else {
1170                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1171                         if (!bh)
1172                                 return -EIO;
1173                         memcpy(data, bh->b_data+offset, tocopy);
1174                         brelse(bh);
1175                 }
1176                 offset = 0;
1177                 toread -= tocopy;
1178                 data += tocopy;
1179                 blk++;
1180         }
1181         return len;
1182 }
1183
1184 /* Write to quotafile */
1185 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1186                                 const char *data, size_t len, loff_t off)
1187 {
1188         struct inode *inode = sb_dqopt(sb)->files[type];
1189         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1190         int err = 0;
1191         int offset = off & (sb->s_blocksize - 1);
1192         int tocopy;
1193         size_t towrite = len;
1194         struct buffer_head tmp_bh;
1195         struct buffer_head *bh;
1196
1197         mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
1198         while (towrite > 0) {
1199                 tocopy = sb->s_blocksize - offset < towrite ?
1200                                 sb->s_blocksize - offset : towrite;
1201
1202                 tmp_bh.b_state = 0;
1203                 err = ext2_get_block(inode, blk, &tmp_bh, 1);
1204                 if (err)
1205                         goto out;
1206                 if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1207                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1208                 else
1209                         bh = sb_getblk(sb, tmp_bh.b_blocknr);
1210                 if (!bh) {
1211                         err = -EIO;
1212                         goto out;
1213                 }
1214                 lock_buffer(bh);
1215                 memcpy(bh->b_data+offset, data, tocopy);
1216                 flush_dcache_page(bh->b_page);
1217                 set_buffer_uptodate(bh);
1218                 mark_buffer_dirty(bh);
1219                 unlock_buffer(bh);
1220                 brelse(bh);
1221                 offset = 0;
1222                 towrite -= tocopy;
1223                 data += tocopy;
1224                 blk++;
1225         }
1226 out:
1227         if (len == towrite)
1228                 return err;
1229         if (inode->i_size < off+len-towrite)
1230                 i_size_write(inode, off+len-towrite);
1231         inode->i_version++;
1232         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1233         mark_inode_dirty(inode);
1234         mutex_unlock(&inode->i_mutex);
1235         return len - towrite;
1236 }
1237
1238 #endif
1239
1240 static struct file_system_type ext2_fs_type = {
1241         .owner          = THIS_MODULE,
1242         .name           = "ext2",
1243         .get_sb         = ext2_get_sb,
1244         .kill_sb        = kill_block_super,
1245         .fs_flags       = FS_REQUIRES_DEV,
1246 };
1247
1248 static int __init init_ext2_fs(void)
1249 {
1250         int err = init_ext2_xattr();
1251         if (err)
1252                 return err;
1253         err = init_inodecache();
1254         if (err)
1255                 goto out1;
1256         err = register_filesystem(&ext2_fs_type);
1257         if (err)
1258                 goto out;
1259         return 0;
1260 out:
1261         destroy_inodecache();
1262 out1:
1263         exit_ext2_xattr();
1264         return err;
1265 }
1266
1267 static void __exit exit_ext2_fs(void)
1268 {
1269         unregister_filesystem(&ext2_fs_type);
1270         destroy_inodecache();
1271         exit_ext2_xattr();
1272 }
1273
1274 module_init(init_ext2_fs)
1275 module_exit(exit_ext2_fs)